The correlation between the molecular structure and inhibitor efficien
cy (E(i)) of triamines was investigated The group-contribution approac
h was adapted to account for Langmuir- and Frumkin-type inhibition. Th
e group contributions (a(j)) were obtained using a nonlinear regressio
n technique. It was assumed that corrosion inhibition was proportional
with coverage, which in turn was accounted for by the Langmuir and Fr
umkin models of adsorption. The multiple correlation coefficient obtai
ned by the linear group-contribution model was improved markedly by us
ing adsorption models. On the basis of these results, a more efficient
inhibitor molecule was proposed.